0x00 PHP扩展进行代码分析(动态分析)
一.基础环境
#!bashapt-get install php5apt-get install php5-devapt-get install apacheapt-get install mysql
二.使用PHPTracert
#!bashmkdir godheadwget https://github.com/Qihoo360/phptrace/archive/v0.3.0.zipunzip v0.3.0.zipcd ./phptrace-0.3.0/extensionphpize5./configure --with-php-config=/usr/bin/php-configmake & make installcd ../cmdtoolmake
编辑 php.ini ,增加:
#!bashextension=trace.so
三.测试
#!php<?php for($i=0;$i<100;$i++){ echo $I; sleep(1);}?>
CLI
#!shellphp test.php &ps -axu|grep php./phptrace -p pid
apache
#!bashcurl 127.0.0.1/test.phpps -aux|grep apache./phptrace -p pid
四.phptrace分析
执行的代码如下:
#!php<?phpfunction c(){ echo 1;}function b(){ c();}function a(){ b();}a();?>
执行顺序是:
#!basha>b>c>echo
参数含义:
名称 | 值 | 意义 |
---|---|---|
seq | int|执行的函数的次数 | |
type | 1/2 | 1是代表调用函数,2是代表该函数返回 |
level | -10 | 执行深度,比如a函数调用b,那么a的level就是1,b的level就是2,依次递增 |
func | eval | 调用的函数名称 |
st | 1448387651119460 | 时间戳 |
params | string | 函数的参数 |
file | c.php | 执行的文件 |
lineno | 1 | 此函数对应的行号 |
日志输出:
#!js{"seq":0, "type":1, "level":1, "func":"{main}", "st":1448387651119445, "params":"", "file":"/var/www/html/2.php", "lineno":11 }{"seq":1, "type":1, "level":2, "func":"a", "st":1448387651119451, "params":"", "file":"/var/www/html/2.php", "lineno":11 }{"seq":2, "type":1, "level":3, "func":"b", "st":1448387651119452, "params":"", "file":"/var/www/html/2.php", "lineno":9 }{"seq":3, "type":1, "level":4, "func":"c", "st":1448387651119453, "params":"", "file":"/var/www/html/2.php", "lineno":6 }{"seq":4, "type":2, "level":4, "func":"c, "st":1448387651119457, "return":"NULL", "wt":4, "ct":4, "mem":48, "pmem":144 }{"seq":5, "type":2, "level":3, "func":"b, "st":1448387651119459, "return":"NULL", "wt":7, "ct":6, "mem":48, "pmem":144 }{"seq":6, "type":2, "level":2, "func":"a, "st":1448387651119459, "return":"NULL", "wt":8, "ct":8, "mem":80, "pmem":176 }{"seq":7, "type":2, "level":1, "func":"{main}, "st":1448387651119460, "return":"1", "wt":15, "ct":14, "mem":112, "pmem":208 }
五.逻辑分析
1.解析监控进程
开一个后台进程一直刷新进程列表,如果出现没有tracer的进程就立即进行托管
2.json提取
通过对每一个文件的json进行提取,提取过程如下:
- 便利所有文件
- 读读取文件
- 提取json,按照seq排序
- 提取 type=2 的与 type=1 的进行合并
- 按照level梳理上下级关系存储同一个字典
- 按照seq排序,取出头函数进行输出
- 提取恶意函数往上提取level直到 level=0
函数对应如下:
#!pythonlist1={ level1:[seq,type,func,param,return] level2:[seq,type,func,param,return] level3:[seq,type,func,param,return] #eval level4:[seq,type,func,param,return]}list2=
3.数据查看
通过追踪危险函数,然后将其函数执行之前的关系梳理出来进行输出,然后再进行人工审查。
放上demo
六.使用XDEBUG
安装
#!bashapt-get install php5-xdebug
修改 php.ini
#!bash[xdebug]zend_extension = "/usr/lib/php5/20131226/xdebug.so"xdebug.auto_trace = onxdebug.auto_profile = onxdebug.collect_params = onxdebug.collect_return = onxdebug.profiler_enable = onxdebug.trace_output_dir = "/tmp/ad/xdebug_log"xdebug.profiler_output_dir = "/tmp/ad/xdebug_log"
放上几个demo图片:
七.优缺点
缺点
人为参与力度较大,无法进行脱离人工的操作进行独立执行。
优点
精准度高,对于面向对象和面向过程的代码都可以进行分析。
0x01 语法分析(静态分析)
案例:
- http://php-grinder.com/
- http://rips-scanner.sourceforge.net/
一.使用php-parser
介绍:
- http://www.oschina.net/p/php-parser
- https://github.com/nikic/PHP-Parser/
二.安装
#!shellgit clone https://github.com/nikic/PHP-Parser.git & cd PHP-Parsercurl -sS https://getcomposer.org/installer | php
PHP >= 5.3; for parsing PHP 5.2 to PHP 5.6
#!bashphp composer.phar require nikic/php-parser
PHP >= 5.4; for parsing PHP 5.2 to PHP 7.0
#!bashphp composer.phar require nikic/php-parser 2.0.x-dev
三.测试
#!php<?phpinclude 'autoload.php';use PhpParser\Error;use PhpParser\ParserFactory;$code = '<?php eval($_POST[c][/c])?>';$parser = (new ParserFactory)->create(ParserFactory::PREFER_PHP7);try { $stmts = $parser->parse($code); print_r($stmts); // $stmts is an array of statement nodes} catch (Error $e) { echo 'Parse Error: ', $e->getMessage();}
输出如下:
#!jsArray( [0] => PhpParser\Node\Expr\Eval_ Object ( [expr] => PhpParser\Node\Expr\ArrayDimFetch Object ( [var] => PhpParser\Node\Expr\Variable Object ( [name] => _POST [attributes:protected] => Array ( [startLine] => 1 [endLine] => 1 ) ) [dim] => PhpParser\Node\Expr\ConstFetch Object ( [name] => PhpParser\Node\Name Object ( [parts] => Array ( [0] => c ) [attributes:protected] => Array ( [startLine] => 1 [endLine] => 1 ) ) [attributes:protected] => Array ( [startLine] => 1 [endLine] => 1 ) ) [attributes:protected] => Array ( [startLine] => 1 [endLine] => 1 ) ) [attributes:protected] => Array ( [startLine] => 1 [endLine] => 1 ) ))
由此可见,我们需要提取出
#!js[0] => PhpParser\Node\Expr\Eval_ Object[name] => _POST[parts] => Array ( [0] => c )
然后进行拼接之后即可发现原始语句是:
#!phpeval($_POST[c][/c])
四.逻辑分析
代码解析
- 通过该库进行语法分析
- 提取结果
- 提取危险函数
- 提取危险函数中存在的变量
- 从上文中提取此变量的赋值方式
- 分析出可控结果
- 输出结果
五.优缺点
缺点
对于面向对象的程序进行分析比较弱。
优点
适合大批量的自动化分析,可以脱离人工操作进行独立执行

Reasons for PHPSession failure include configuration errors, cookie issues, and session expiration. 1. Configuration error: Check and set the correct session.save_path. 2.Cookie problem: Make sure the cookie is set correctly. 3.Session expires: Adjust session.gc_maxlifetime value to extend session time.

Methods to debug session problems in PHP include: 1. Check whether the session is started correctly; 2. Verify the delivery of the session ID; 3. Check the storage and reading of session data; 4. Check the server configuration. By outputting session ID and data, viewing session file content, etc., you can effectively diagnose and solve session-related problems.

Multiple calls to session_start() will result in warning messages and possible data overwrites. 1) PHP will issue a warning, prompting that the session has been started. 2) It may cause unexpected overwriting of session data. 3) Use session_status() to check the session status to avoid repeated calls.

Configuring the session lifecycle in PHP can be achieved by setting session.gc_maxlifetime and session.cookie_lifetime. 1) session.gc_maxlifetime controls the survival time of server-side session data, 2) session.cookie_lifetime controls the life cycle of client cookies. When set to 0, the cookie expires when the browser is closed.

The main advantages of using database storage sessions include persistence, scalability, and security. 1. Persistence: Even if the server restarts, the session data can remain unchanged. 2. Scalability: Applicable to distributed systems, ensuring that session data is synchronized between multiple servers. 3. Security: The database provides encrypted storage to protect sensitive information.

Implementing custom session processing in PHP can be done by implementing the SessionHandlerInterface interface. The specific steps include: 1) Creating a class that implements SessionHandlerInterface, such as CustomSessionHandler; 2) Rewriting methods in the interface (such as open, close, read, write, destroy, gc) to define the life cycle and storage method of session data; 3) Register a custom session processor in a PHP script and start the session. This allows data to be stored in media such as MySQL and Redis to improve performance, security and scalability.

SessionID is a mechanism used in web applications to track user session status. 1. It is a randomly generated string used to maintain user's identity information during multiple interactions between the user and the server. 2. The server generates and sends it to the client through cookies or URL parameters to help identify and associate these requests in multiple requests of the user. 3. Generation usually uses random algorithms to ensure uniqueness and unpredictability. 4. In actual development, in-memory databases such as Redis can be used to store session data to improve performance and security.

Managing sessions in stateless environments such as APIs can be achieved by using JWT or cookies. 1. JWT is suitable for statelessness and scalability, but it is large in size when it comes to big data. 2.Cookies are more traditional and easy to implement, but they need to be configured with caution to ensure security.


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